I just got a 55nm GTX 260. I was hoping that it has a fix for the video corruption problems that exist when PowerMizer kicks in and throttles the clock rate. No such luck - the problem is still there. If you click on the application launcher of KDE4 (at the bottom left) and then try to drag an icon (such as the help ring buoy), the whole screen will flicker. This doesn't happen if the card is forced to stay at the normal clock rate.

I just pulled the PerfLevelSrc setting from the kernel module options to try and lower the temperature on my GTX260 and immediately noticed this when dragging links in Firefox 3 or even just moving focus between Firefox 2 and another window. Awful. :S